Mold and method for casting electrolytic cells



A. w. MOORE ETAL v MOLD AND METHOD FOR CASTING ELECTROLYTIC CELLS 5 Sheets-Sheet 1 Filed Dec. 4, 194;.

lll/ll I l [TTY , Oct. 2', 1945,.

' MOLD' AND METHOD FORYGASTING ELEcTRoLYTIc CELLS A. w.A MOORE ETAL Filed Dec. 4, 1941 s .sheets--sxgeetr 2l Oct; 2,y '1945. K l A, w MOORE ErAL- Y 2,335,830

MQLD AND METHOD FOR CASTING ELEC'.I'BOI..YTIc CELLS Filed beg. 4, 1,941" s sheeisfsheet s` Peienied oei. z, 194s UNlrEo STATES Pii'riezN'r oFFlcla:H

MOLD AND METHOD FOR CASTING ELECTROLYTIC- CELLS Alexander Whiteside Moore and Frank Benjamin Moran, Trail, ,British Columbia, vHerbert y Louis Christian, Rossland, British Columbia,

and Darcy Drummond Morris, Calgary, Alberta, Canada, assignors to The Consolidated Mining and Smeltlng Company of Canada, Limited, Montreal, Quebec, Canada, a companyV of Canada Application December 4,1941, seriei No. 421,656 1 (ci. 25e-#130) Claims.

yThis invention relates to a method and apparatus for the `manufacture of combined gas collectors and cell covers for electrolytic cells of the tank type.

In a co-pending application Serial No. 276,158, a combined gas collector and cell cover for electrolytic cells of the tank type is disclosed. The cell cover incorporates, in a unitary casting, the gas collecting chambers for the separate collection of the gases resulting from the electrolytic decomposition of solutions. The cell cover is cast of non-conductive material and includes side walls, end walls, a top, and Va bottom, forming a chamber therebetween. A gas-tight partition extends from the bottom to the top of the chamber thereby dividing the chamber 'into two gas collecting chambers. `Alternate positive and negative electrodes are suspended from the cover. Ports and inverted channels are formed in the bottom of the cell cover, each port being aligned with an inverted channel. Each port 'and the inverted channel with which it is aligned is located over an electrode. Each port and its respective channel meet and terminate immediately below the gas-tight partition in such a manner that the ports above the positive electrodes extend into one of the gas collecting chambers and the ports above the negative electrodes extend into the other of the gas .collecting chambers.` Provision is also made to prevent'- intermixing of the gases evolved at the positive and negative'electrodes during electrolysis.

In casting hollow structures, particularly those of cement or concrete, provision must be made forremoving the core, or internal. mould., which forms the hollow in the casting after the casting has solidified. 'In casting a structure of the type described hereinabove, a problem i's encountered in removing the cores which form the gas collecting chambers in the casting, after the casting has solidified. Several expedients were followed,`such as, foi example, by leaving in the castings, openings large enough to provide for the removal of the solid cores used for Aforming the gas collecting chambers, each opening subsequently being sealed by a cover cemented in place to form a unitary structure. The weakest points in a casting made by this method v'were found to be along the joints where theopenings had been sealed and the resulting structure was found to be not entirely satisfactory in use.

One of the principal objects of this invention is to provide an arrangement of mould and core parts whereby-the combined gas collectors and cell covers for electrolytic cells of the tank type 55` ing cores;

can be cast in one piece without lines or points of weakness.

A further object of the invention is to provide an arrangement of mold and core parts which is readily assembled and disassembled and ywhich can be separatedreadily from the nished solidifled casting. r Y

A clear understanding of the objects ofthe present invention, and the manner in which they are attained, may be had from the following description and accompanying drawings, in which:

Figure 1 is a perspective view, partly in cross- `section and partly cut away, of a combined gas collector vand cell cOver for electrolytic cells of the tank type constructed in accordance with the present invention;

Figure 2 is a cross sectionalr end elevation of the cell cover, taken along the line 2 2, Figure 1; the section being ytaken through the cathode supporting rods;

Figure 3 is a side elevation, slightly in perspective, of the side and end forming framework of the wooden form used in .the manufacture ,of the cell cover; l

Figure 4 is a4 top'plan view of the bottom of the mould with the gas channel and groove forming cores assembled; Y

Figure 5 is a side elevation showing.v the alter#- nate positions of the oxygen and hydrogen gas channel forming cores;

Figure 6 is an end elevation of the gas channel forming cores shown in Figure 5;

Figure 7 is an end elevation showing the gas channel and groove forming cores in place;

Figures 8 and 8a are detail views of the bevelled strip assembly;

. Figure 9 is a detailof the electrode port form- Figure 10 is a cross-sectional side-elevation showing the assembled form with the fusible cores for forming the gas collecting chambersin l I oxygen, resulting from the electrolytic decomposition of water, arel separately collected in a high state ofV purity.

- ductive material, such as concrete. and is formed c their respective. gasometers.

-top 3 of the cover.

with side walls, |,endV walls 2, a top 3 and a boty, ftonedforming. a chamber therebetween divided approximately midway of its length, by the gastight partition Ii,

l into two 'gas collecting chambers.

The top, 3 of the cell cover is slightly larger in assenso itto the point below the gas-tight partition I, at which point the channel opens into the gas port with which it is in alignment. The vertical cross-section of .each inverted channel, therefore', is lgreatest at the `section where the gas ilow through that channel iskgreatest, namely,

area than the-area enclosed by the upper rim of formly upon the upper rim of the tank.

`The gas-tight partition I divides the interior of the cell lcover into the hydrogen collecting .chamber 9 and the oxygen collecting chamber Il. The hydrogen chamber y9 is made' preferably slightly longer than the oxygen chamber lin orderto-accommodate the cathodes, the number of which, in the preferred modication of our invention, exceeds by one the number of -anodes.

.'I'he gases collected therein are withdrawn through pipe couplings I I and I la respectively to The negative and positive electrodesi I2. and I8 respectively. are suspended from the cover 3 and are secured thereto by means of vertical supporting rods I4. The lower ends of rods Il are suitably welded or riveted t'o their respective electrodes, as shown in Figure 2, while the upper ends are threaded and extend upwardly through openings I provided for that purpose in partition 5.

When' the electrodes are drawn into position, their -upper edges are prevented from touching the cell tank and protrudes beyond the sides and" ends thereof to form a flange which rests uni- 10 at the section above the centre of each electrode where thechannel. immediately thereabove opens `into the gas port with which it is in alignment. The gases in channels I9a and 29a flow in opposite directionsbefore being discharged through ports I9 and 2,0 into chambers! and 'I9'. respectively. It will be understood, of course, that this feature of the invention can be applied inother modications such as where the floors of chambers 9 and In and the ceilingsof channelsIIa and a are formed horizontally.

In o ur preferred and gther modifications, the bus-bars I'I are passed through tapered slots I'Ia provided in the top I of the cover' and are riveted or welded to the positive electrodes I3.

We have -found it/ most' convenient to pass .the

l bus-bars I1 'through the oxygen compartment and downwardly through the. ports 20' to contact the anodes directly beneath those ports. Similarly, the bus-bars I9 are passed through ports' I9 to be joined t5 the negative electrodes I2.

-When thewassembly is completed. the taperedy the bottom of the cover by means of detachable saddles or spacers 29, which are placed aty each end of the upper edge of each electrode. The electrodes are drawn tightly into place by means of nuts and washers I9 acting upon the threaded upper portions of rods Il. These nuts and washn ers IB are countersunk in the upper surface of the When the electrodes are in 40 place, we prefer to cover the countersunk nuts and washers I6 with a mixture, such as cement grout, to provide' the top of the smooth uniform surface.

Gas ports I9 and 29 and inverted channels I9a and 20a are formed in the underside of the bottom of the cell cover, each gas port being aligned with an inverted channel. A gas port I9 and an inverted channel I9a with which it is aligned is located over each cathode^l2 and a gas port v20 cover with a 1 slots I'Ia and y Ila are, made gas-tight;` by sealing around the bus-bars, preferably with a cement grout.r

A nipple ss extends through' the top of the v cover into each oi.' the gas collecting chambers.

These nipples are normallyclosed to prevent the escape of gas but may tbe usedto withdraw gas samples from the respective chambers. The pipe 61 extends through the cover into the electrolyte in one ot the chambers'and servesto indicate when the level of the electrolyte has fallen below a predeterminedlevel.

` Y In the preferred embodiment of our invention described and illustrated herein, vwe enclose each Aoi the positive electrodes rcompletely with a porous diaphragm 2I, preferably formed of such materiales woven asbestos cloth. lGrooves 23 are formed in the underside of the bottom 4` of the cell cover and extend along its entire length 'and are spaced parallel to, on each side of and and an inverted channel 20a with which itis aligned is located over each anode I9. -Each gas ,port and its respective channel meet andl terminate immediately below the gas-tight partition in. such amanncrthat the ports I9 above the cathodesextend into the hydrogen collectingchamber 9 andthe ports n2li above the anodes extend intothe oxygen collecting chamber I9.

Each port I9 and 20 extends substantially along the tull width of the bottom of its respective gas substantially equidistant from the channels 20a. 'I'he top edge of each' of the asbestos diaphragms is tightly wedged into the appropriate grooves 23 by means of iron strips 24. 'No diaphragms surroundI the cathodes but an asbestos skirting 25, fastened around the bottom edges of the cover bymeans of iron straps, `extends downwardly to a point' Justeabove the bottom of the I cell tank.-

collecting chamber, and the` inverted, channel y which it meets and with which it is aligned extendssubstantially along the full width of the bottom of the other gas collecting chamber.

In the preferred modification ofthe invention described and illustrated herein, the door of each of the gas collecting` chambers 9v and I9 slopes uniformly downwardly from the base of the vertical gas-'tight partition i along the width of each chamber to the base ofl the outer wall of that chamber. y y f The ceilingoi' each inverted channel is formed parallelto the slopingffloor of the gas collect-L ing chamber directly above'it, extending `from the corner of the electrode'immediately beneath around them, they aid in shaping the diaphragm g bags and also serve to prevent, these bags from touching the electrodes. The spacers ,29h are provided at the bottom of the vertical edges of each electrode to prevent the electrodes from n trolyte. in the cell. A form of circulating device is illustrated in Figure 1 and comprises a cou-r Provision is also madev for circulating the elec-r aaaasao hun; u, one end of which extends through the end wall of the gas collecting chamber below -the level at which it is desired to maintain the" which would otherwise tend to become progressively more highly concentrated in the gas co1- lecting chambers and less concentrated in the other partsvof the cell.

It has beenfound that concrete, preferably reinforced. is an idealv material for use in the construction of the cell cover described hereinabove. While a number of diiferent mixtures of cement and aggregate may be used. it is preferred to use a mixture composed of one part of Portland cement to one part of quartz sand, which gives a dense, hard andstrong concrete. In constructing the cell cover, a reinforcing framework is used, made up of steel rods of approximately 1/4" diameter, which are spot welded and completely. covered by the concrete. 'Ihe method and apparatus for the manufacture of this cell cover is described in detail hereinafter, particular reference being made to Figures 3 through l1 of the drawings.

The vconcrete cover is cast 'in one piece using an arrangement of forms andf cores which is readily disassembled after the casting has solidined and which is readily separable from the casting after solidiflcation.

The rectangular side-forming framework is i1- lustrated in Figure 3 and includes the side members 40 and end members 4I secured together by tie bolts 42. The side and end members are preferably joined in mortise and tenon :loints` as indicated ai;

The bottominside edge of each side and end member 4l and 4l is bevelled, as indicated at 44, to receive a removable strip ofwood 40. Each hevelled strip 4s 1s drilled along lts length to fo'rm substantially equallyspaced aligned holes 41 in which are received the aligned bolts 4I, as shown in Figure 8, the heads of which project outwardly i from the strips and which, ultimately, are imbedded in the finished casting.

Between the holes 41, vertical slots are formed in the strips in the end members".

AEach of the slots 4l in one end strip l. is in alignment with a Acorresponding slot in the opposite end strip. Tlle slots are preferably equally spaced and the vnumber is dependentA upon the number of individual electrodes to be enclosed by the diaphragm bags.

Y A collar l0, shown in part in Figure 3, is built around the top periphery of the frame members 40 and. and extends outwardly therefrom wto form the iiange on the ,top I of the cell cover.

The bottom forming member Il, on which the side for'ning frame rests, is preferably slightly longer and wider `than the frame and may be detachably secured to the underside of the members 40 and ll.' 'I'he bottom liA is preferably formed of wood of suiilcient thickness to support the weight oi' the forms, cores and casting.

The gas channel forming cores l2 and Il and the cores 54 for forming the grooves, into which grooves the asbestos diaphragm bags 2l are wedged in the finished casting. are' secured to and extend upwardly fromth'e upper surface of ,the bOttOm Ill Each of the gas channel and groove forming cores 52, 53, il, as illustrated in Figures 4 and 7, is preferably fm'ade of wood and covered with a thin sheet of zinc in order that it may be easily withdrawn from the casting after it has solidified.

I'he gas channel and groove forming cores are formed with fiat bases whichv are wedged into slots formed in the upper surface of the bottom member Il, as shown in Figure 5. These slots extend between the end members 4I.

For'the purpose of description, the cores 52v are are in alignment closer to one end of the bottom member 5I and the high points 52a are in alignment closer to the opposite end.

Each of the groove forming cores 54 is spaced approximately midway between each pair of gas channel forming cores.

If desired, and particularly when it is desired to form very narrow gas channels, the

vchannel forming cores may be made of low terne perature fusible material, such as parailin wax.

The surfaces of the bottom forming and-side forming members exposed to the concrete are treated with Vaseline or like non-saponiilable material to prevent adherence of the concrete.

The side forming frame is then. lowered onto.

the bottom form with the ends of the groove l forming cores 5I fitting snugly into the slots l0.

' The gas collecting chambers are formed by means of low temperature fusible cores l5, such as paraffin waxcores, which are moulded into the desired shape as described in detail hereinafter.

Each fusible core 55 rests onthe alternateA gas channel forming cores at its respective end of the mould such that the high points 62a and 53a of the channel forming cores form openings in the finished casting extending into the respective chamber immediately above, as illustrated in Figures Yl0 and l1.

-cores rest. We prefer to place the brads 5 1 on the outermost cores.

A reinforcing structure l0, preferably made up of one-quarter inch mild steel rods, as illustrated in Figure 10,`is lowered into the mould form simultaneously with the gas collecting chamber forming fusible cores. v

Y 'I'he reinforcing structure i6 is supported on small blocks Bl. formed of a material such 'as that sold under the trade name 'Iransite. which vare placed on the top of the wax cores in suchv a manner that, after. casting, the reinforcing structure is completely imbedded in the concrete.

The V-shaped slots ila and lla in the top of thecver, through whichv the electrode connec- As illustrated in Figrell. one of the fusible f cores is made somewhat longer than the otherv in order to form a hollow chamber of a size sumcientto accommodate the cathodes, the nurnwedge shaped core members Il. Each set of these cores is attached to awoodenstrip ill, as illusl 'trated in Figure.- Two setsof wooden strips 'the cover. i All the cores It rest uniformly on the 'fusible cores BB so that the slots, formed bythese l the finished cover. a Openings in the top of the. cover forthe elect.

ftrade-hangers are formed by iron rod cores y6|. i These cores are supported by a template which, f in turn, is supported by theside members Ill. l' The lowermost ends of the, cores Il are preferi jcores, open into the gas collecting chambers in.'

ably taperedunifomily to e relatively small dl- 'ameterto t into the holes I8. shown in Figure 4,

formed in the gas channel forming cores.

in fixed position by a 1 side members 40.

The pipe couplings 4I l /and -I I a are provided in the top of the cover for the separate withdrawal of the gases from the respective gas collecting chambers and for cleaning the interior of the chambers. The lower ends ofthe couplings are 'i pressed w a slight extent into the fusible core immediately below. The couplings may be held template carried by the The couplings It are placed horizontally and held in place between the end members 4I f and the fusible cores, preferably lclosevto the bottom l of the chamber forming cores.

In Figure 11 are shown nipples l and the pipe il which are in the form of shortpieoes of l Pipe, the lower ends .of which are pressed to a t v slight extentintq the fusible core immediately j below. The nipples may be held in fixed posil tion by a template carried by side members I0.

' v1 These nipples are used subsequently for the purpose of withdrawing gas for analysis from the l gas collectingl chambers. In the operation of the electrolytic cell, the pipe i1 serves to indicate to t the operator when the level of the electrolyte in l the cell has fallen below a predetermined level.`

We have found, when using solid fusible cores',

v 3 that unless the heat, which is generated. during the setting of the concrete, is removed by sumcient cooling, the fusible cores tend to expand and crack the concrete. lWehave overcome this difficulty by using vfusible cores of hollow construction and have found that these hollow fusible cores expand inwardly without causing excessive stresses in the concrete.

\ In instances whererthe fusible core is in the i form of a hollow shell, as illustrated in Figure 10 anddescribed in detail hereinafter, it is 'preferre'd to-have each yof the couplings vIl and ila 1 extend a short distance `into the shell ofI each core. Each coupling communicates withan opening extendingrinto the interior of the shell to p provide for the relief of any pressure on the walls t of the'cores' resulting from the expansion of the l air in the ,interior of the cores due to the heat evolved during the setting of the concrete.

'in the castings tol gain access to solidlned. When the concrete has solidified, the

side and end frame members 4l and 4l may be removed and after the setting period has elapsed,v the casting may bev lifted fromy the bottom lform 5I.

The fusibleicores `55 are removedfby heating the casting to a temperature above the melting temperature of the core.v When using a paraffin wax core,we prefer to immerse' the `casting in a bath of cold water, the temperature of .which is then raised to'about 158 F. The casting is maintained at this temperature for .a period of time Q sui'iiclent to permit the wax to melt and'escape through one or more of the openings communieating with the gas collecting chambers.

` When the bulk of the wax has been removed, the residual wax remaining in the hollow interior may be removed by means of live steam injected thereinto preferably facilitated' by submerging they casting in a bath of hot water.

in the usual manner.

It has 'been` found that a core, or internall mould, of suillcient tensile strength to withstand the weight vof the material cast aroundit. can

be formed of material which is fusible at a relatively low temperature, such as tparailln wax.

` which is. readily fusible atfa relatively low temperature, and when in liquid form, is highly fluidl and easily removable from the chambers formed in the casting through orifices which are provided the hollow interior. A

It has been found' that a core formed of a high grade paraffin wax'having a melting point yof y; from 133g F. to 163 F. is very satisfactorybut it will beclearly understood that equally' satisfac-- tory results can be obtained from other materials having relatively low melting points and relatively high fluidity when in the molten state.

The fusiblevcore is very'easily formed by pouring the molten material. such as parailin wax,

into a mould of suitable shape formed in a col.- lapsible core box which may be constructed of l wood or of other-suitable material.` The core box is preferably constructed in such a manner as to be easily disassembled when the core has set. The surface of the mould in the core box is preferably formed of material such as zinc or treated in sucha manner as to present a surface to which the wax does not adhere. In this respect, the surface of the mould so exposed to the wax should be of a nature as to retain" its original form when the core box is assembled and when exposed to the heatv ofthe molten wax' r lpoured into it.

The assembled form is ready toreceive thel concrete, during the pouring of which avvibrator (not shown) is alternatelyv clampedon each end member 4| -to facilitate the flowing of the conffll may be rotated to loosen them in order to per- 'me mould in the assembled e'ore box issued with moltenwax and then cooled, preferably by 'submerging the core box in cold water until the Y wax has solidified and hardened. The core box then may be disassembled and thevfusiblel corey removed yfrom the mould* i y The core.' prior to use, .is usually trimmed Nto remove any irregularities at its corners and its surface and is then 'ready for use.l

In casting concrete, heat is developed during the setting. solid fusible cores are notl ordinarily affected by this heat unless the volume of concrete poured is such that the amount 1 of heat developed would tend to cause deformation of the core before the concrete hadset. in which case provision would lhave to be made `to maintain the c ore at a temperature below that aty which lsuch deformation would occur. As noted l K After the wax has been removed. the eastingmay be cured ing use,

that openings previously. the fusible cores should have a relatively low melting temperature, but the melting V Y temperature must be abovethe formation temperature of the casting, that is, above the temperatures encountered during pouring and setting of the casting.

A furthr advantage results from the use of hollow, rather than solid, fusible cores, in that l appreciable economy in core material is effected when the cores are produced in quantity. The hollow cores may be made by limiting the period of time of soiidiflcation of the wax in the cold water. As the wax hardens from the outside to y the opening in the shell is covered with a moulded the resulting casting, and reinforcing means supported by said fusible cores.

3. A mould and core construction for casting,

A in onel piece. a combined gas collector and cell cover for electrolytic cells of the tank typevwhich v comprises a bottom forming member, parallel and alternatelyspaced` channel forming fusible cores and groove forming solid cores supported by said bottom member and extending upwardly therefrom, spaced apart side and `endforming memberssupportedby said bottom member and en'- closing said parallel cores, and fusible cores supported by said channel forming cores, said fusible cores having a relatively low melting temperature which is above the formation temperature of the casting, and detachable cores extending .upwardly from said fusible cores above the uppermost wax plate which is sealed in place with molten wax, and the core is ready for use. While awaitthe cores are usually stored in cold water. In using, a hollow fusible core, as described hereinabove, it is usually advisable to make provision for relieving the pressure in the interior of the core. This pressure is caused by the expansion of the air due to the heatdeveloped during the setting of the concrete, It has been found M, as shown in Figure 10, extending through the shell`of each hollow core and communicating with'coupllngs Ii and ila, act as air release vents and serve to rprevent any increase in the pressure Withinl the hollow core.

It-will be understood that modifications of the preferred embodiment of our invention may be made by others skilled in the art, in the light of the teachings herein, without departing from the scope of the inventiony as defined in the appended claims.

What we claim as new and desire to Letters Patent ofthe United States is:

1. A mould and core construction for casting, invone' piece, a combined gas collector and cell cover for electrolyticcells of the tank type which comprises abott'om forming member, parallel and alternately spaced channel and groove forming cores supported bys'aid bottom member and extending upwardly therefrom, spaced apart side and end forming members supported by said bottom member and enclosing said parallel cores,

protect by and fusible cores supported by said .channel forming cores, said fusible cores having a relatively low melting temperature which is above the formation temperature of the casting, and detach-- able cores extending upwardly from said fusible cores above theuppermost surface of the resulting casting. y

2. A mould .and core construction for casting,

in one piece, a combined gas collector and cell cover foij'electrolyticy cells' of the' tank type which comprises a bottom forming member, ,parallel and alternately spaced channel and groove forming cores detachably secured to said bottom member and extending upwardly therefrom, -spaced apart side and end forming -members supported byI said bottom` member and enclosing said parallel cores, and fusible cores supported byysald channel forming cores, said fusible cores having a relatively low melting temperature which is above the formation temperature of the casting,

and detachable cores extending upwardly ,from

said fusible cores above theuppermost surface of surface of the resulting casting.

, i4. A mould and core construction for casting,

in one piece, a combined gas collector and cell cover for electrolytic cells of the tank type which comprises ra, bottom forming member, parallel and alternately spaced channel and groove forming'cores supported by said bottom member and extending upwardly therefrom, spaced apart side and end forming members supported by said botopening extending from the 'hollow interior of the4 fusible core to the atmospherer L r 5. A mould and core construction for casting, in one piece, a combined 'gas collector and cell cover for electrolytic cells of the tank type which comprises a bottom forming member, parallel and alternately spaced channel and groove forming cores supported by said bottom member and extending upwardly therefrom, each of said channel forming cores sloping uniformly upwardly fromach end to a point spaced apart a predetermined distance from the central vertical axes of said cores, said channel forming cores being alternately'positioned'whereby the highest points of one 4set of alternately spaced channel forming cores are in alignment on one side of the central vertical axes. of the said cores andthe highest points of the other set of alter-y nately spaced cores are on the other sideof said vertical axes, spaced apart side and end forming members, 4enclosing said parallel cores, and spaced apart fusible cores supported by said channel forming cores, a fusible core being supported by thehighest partof each set of said cores and ex,

. tending the full width thereof, said fusible cores having a relatively low melting temperature which is above the formationgtemperature of the casting, and detachable cores extending upwardly from said fusibleY cores above the uppermost surface of the resulting casting.

6. A mould and core construction for-casting, in one piece, a combined gas collector and cell cover for electrolytic cells of the tank type whichy comprises a bottom forming member, -parallel and alternately spaced channel and groove forming cores supported by said bottom member andl extending upwardly therefrom., spaced apart side andend forming members supported by said bottom members and enclosing said. parallel cores', and two spacedapart fusible cores supported by said channel forming cores, a'fusible core being positioned on each side of the vcentral y vertical axes of said parallel cores and' extendv concreteto solidify, removing the form and pary ing the full width thereof, said fusible cores havl i lng a relatively low melting temperature which 'is above the formationv temperature of the casting,

and cores extending upwardly from, said fusiblev cores above the uppermost surface of the resulting casting, and detachable cores supported by if said side forming members 'and extending downwardly between the fusible cores and terminating at said channel forming cores.

-7. A mould 'and core construction for casting,

in one piece, a combined gas collector and cell cover for electrolytic cells of the tank type `which comprises a bottom forming member, parallel and alternately spaced` channel yand groove forming cores supported by said bottom member and extending upwardly therefrom, spaced apart side and end forming members supported by said bottom member and enclosing said parallel cores; and

vfusible cores supportedl by said channel forming cores, said fusible cores havingv a relatively low melting temperature which is above the forma# tion temperature'of the casting, detachable cores supported by theside forming members and ex-` tending downwardly and terminating at said channel forming cores, cores 'extending upwardly from said fusible cores, and at least onecore exlallel cores, land heating the casting to a temlow melting temperature which is above the for mation temperature of the resulting casting, en

closing the'parallel cores with a form of predetermined Aheight above the chamber forming y fusible cores,` filling the form with concrete and permitting-the concrete to solidify, removing the.

form and parallel 'solid cores, and heating the casting to a temperature above themelting temperature of the said fusible core material, and

removingthe moltencore through openings in the'casting'.

10. The method of casting, in one piece, a combined gas cpllector and cell cover for electrolytlc cells of the tank type which comprises erecting,

on a base, a plurality of parallel and alternately spaced, upwardly extending channel and groove forming cores,vand supporting, on the'parallel channel forming cores, hollowfuslble cores hav I f ing a relatively low melting temperature whichis tending horizontally from eaclfusible core' to the end forming member adjacent thereto. n

8.` Themethod of casting, in one piece, a cornbined gas collector and cell cover for electrolytic Acells of the tank type which comprise erecting;

on a base, a plurality of parallel and alternately spaced, upwardly extendingchannel and groove forming cores, and supporting, on the parallel channel forming cores,jfusible cores havingv a .relatively low melting temperature which is above the formation temperature of the resulting casting, enclosing ythe parallel cores with a form of predetermined heightv above the fusible cores,

lling the form with concrete and permitting the f above the formation temperature ofthe resulting casting, enclosing the parallel cores with a form of predetermined lheight above the hollow fusible cores, filling theform with concrete and permitting the concrete to solidify, removing the form 4 and parallel cores, and heating .the casting to a temperature above the melting temperature'of the fusible cores, and removing the molten core n material through openingsin the'casting.

ALEDIANDER WHITESIDE MOORE. FRANK BENJAMIN MORAN." f

HERBERT LOUIS CHRISTIAN.

DARCY DRUMMOND MORRIS. 

